Determination of Dynamic Equivalent Boundary of AC-DC Power Systems Considering AC-DC Coupling

Faced with the rapid development of UHV AC-DC transmission technology and networking technology, the power grid pattern has undergone great changes, making the impact of faults on the system global, so transient security assessment is need. To accurately simulate the dynamic characteristics of the AC-DC power systems after fault in the evaluation process while reducing the simulation scale and calculation amount, it is necessary to use a dynamic equivalent to represent the systems. The determination of the equivalent boundary usually has a great influence on the dynamic performance of original system. Therefore, this paper analyzes the coupling between AC and DC systems by simulating the dynamic characteristics of AC-DC power systems with different equivalent boundaries and evaluating the DC response after faults occurring at different locations of the AC system, which provides guidance on the determination of dynamic equivalent boundary.